Pt Sub‐Nanoclusters on ZIF‐Derived Ultrafine Cd _<i>x</i> Zn _{1− <i>x</i>} S Solid Solution: High‐Performance Photoreforming Lactic Acid to H ₂ and Value‐Added Chemicals

ABSTRACT Solar‐driven H 2 production coupled with selective organic transformation represents a promising strategy for co‐generation of green hydrogen and high‐value chemicals, yet its feasibility relies critically on effective bifunctional photocatalysts. Herein, we report the synthesis of ultrafine Cd x Zn 1− x S nanocrystals derived from a zeolitic imidazolate framework (ZIF), featuring high surface area, shortened charge diffusion path, and enhanced H 2 evolution activity. Anchoring amorphous Pt sub‐nanoclusters onto these nanocrystals created a bifunctional catalyst (Pt‐Cd x Zn 1− x S) for efficient lactic acid photoreforming, enabling co‐production of H 2 with switchable selectivity toward pyruvic acid (PA) or 2,3‐dihydroxy‐2,3‐ dimethylsuccinic acid (DTA). The optimized 0.5Pt‐Cd 0.3 Zn 0.7 S catalyst achieved an exceptional H 2 production rate of 270.6 mmol h −1 g −1 , 73.1% PA selectivity, and 62.8% apparent quantum efficiency at 400 nm. Mechanistic studies revealed that lactic acid undergoes C‐H cleavage to form carbon‐centered radicals. Pt sub‐nanoclusters served as electron sinks to facilitate O‐H dissociation and PA formation, whereas pristine Cd 0.3 Zn 0.67 S promoted direct C‐C coupling of radicals to predominantly yield DTA. This work offers critical insights for designing advanced bifunctional photocatalysts to integrate solar hydrogen and value‐added chemical synthesis.